Abstract

Background:

Obsessive–compulsive disorder (OCD) is a severe mental illness. OCD symptoms are often resistant to available treatments. Abnormalities within the orbitofronto-striato-pallido-thalamic circuitry, especially orbitofrontal cortex (OFC) hyperactivity and cerebellar hypoactivity have been observed in patients. Non-invasive brain stimulation studies have indicated that transcranial direct current stimulation (tDCS) may be a useful alternative to alleviate treatment-resistant symptoms in various neuropsychiatric conditions.

Methods:

In an open-label pilot study, 8 patients with treatment-resistant OCD received 10 sessions (twice a day) of 2 mA tDCS applied with the cathode over the left OFC and the anode over the right cerebellum. OCD (Y-BOCS and OCD-VAS) as well as depressive (MADRS) symptoms were measured 4 times: one time before tDCS and 3 times after (immediately after, 1 and 3 months after the 10th tDCS session).

Results:

We reported a significant 26.4% (±15.8) decrease of Y-BOCS score (p = 0.002). The beneficial effect lasted during the 3 month follow-up. No effect of tDCS was observed on depressive symptoms. At end point, 5 out of 8 patients had a decrease of ≥25%; and 3 out of 8 patients had a decrease of ≥35% in Y-BOCS score. tDCS was well tolerated.

Conclusion:

tDCS with the cathode placed over the left OFC combined with the anode placed over the right cerebellum is a suitable and safe approach to decrease OCD symptoms in patients with treatment-resistant OCD. Large scale randomized controlled studies are needed to confirm this promising result.